Background
Despite widespread advocacy for shared decision making (SDM), the
empirical evidence regarding its effectiveness to improve patient outcomes
has not been systematically reviewed.
Purpose
To systematically review the empirical evidence linking patient
outcomes and SDM, when the decision-making process has been explicitly
measured, and to identify under what measurement perspectives SDM is
associated with which types of patient outcomes (affective-cognitive,
behavioral, and health).
Data Sources
PubMed (through December 2012) and hand search of article
bibliographies.
Study Selection
Studies were included if they empirically (1) measured SDM in the context of a patient-clinician
interaction, and (2) evaluated the
relationship between SDM and at least one patient outcome.
Data Extraction
Study results were categorized by SDM measurement perspective
(patient-reported, clinician-reported, or observer-rated) and outcome type
(affective-cognitive, behavioral, or health).
Data Synthesis
Thirty-nine studies met inclusion criteria. Thirty-three used
patient-reported measures of SDM, six used observer-rated, and two used
clinician-reported. Ninety-seven unique patient outcomes were assessed;
51% affective-cognitive, 28% behavioral, and 21%
health. Only 43% of assessments (n=42) found a significant and
positive relationship between SDM and the patient outcome. This proportion
varied by SDM measurement perspective and outcome category. 52% of
outcomes assessed with patient-reported SDM were significant and positive,
compared to 21% with observer-rated and 0% with
clinician-reported SDM. Regardless of measurement perspective, SDM was most
likely to be associated with affective-cognitive patient outcomes
(54%), compared to 37% of behavioral, and 25% of
health outcomes.
Limitations
The relatively small number of studies, precludes meta-analysis. The
study inclusion and exclusion criteria requiring both an empirical measure
of SDM as well as an assessment of the association between that measure and
a patient outcome, resulted in most included studies being observational in
design.
Conclusions
SDM, when perceived by patients as occurring, tends to result in
improved affective-cognitive outcomes. Evidence is lacking for the
association between empirical measures of SDM and patient behavioral and
health outcomes.